Influence of Dietary Urea on Performance, Antibody Production and Hematology of Growing Swine

Abstract

Gain and hematological comparisons were made over a 69-day period among growing pigs receiving a 17% crude protein basal ration and pigs receiving 2.5% urea, either added to the basal making it 23% protein equivalent or replacing an equivalent amount of protein nitrogen in the basal ration. Inclusion of urea in the ration depressed rate and economy of gain during the 29- to 42-day period with subsequent improvement during the final 27 days of the experiment. The greatest initial gain depression and subsequent improvement were in the group in which urea replaced a portion of the basal protein. Pigs receiving urea had significantly increased serum urea and reduced serum ammonia concentrations at 32 days, but not at 69 days. Serum protein concentrations were significantly higher in males than in females. Rations had no effect on serum protein concentrations. Hematocrit, hemoglobin and leukocyte values were not different among treatments. Antibody response to Salmonella pullorum antigen was not affected by dietary urea. No symptoms of urea toxicity were noted. Copyright © 1965. American Society of Animal Science . Copyright 1965 by American Society of Animal Science